Cutout is characterized by decreases in growth rate, flowering, and boll retention. It can be hastened by a nitrogen deficiency. Indole-3-acetic acid (IAA) is a N-containing plant growth hormone that inhibits abscission. We conducted a field experiment with 'Deltapine 61' cotton to determine if IAA content of fruiting branches decreased as the plants entered cutout. Nitrogen was supplied at 0 and 150 kg/ha with four replications in a randomized block. Fruiting branches, beyond the first node, were harvested periodically during the season. Each branch was harvested 3 days after a flower opened at the first node. All fruiting forms were removed. Average length of fruiting branches (beyond the first node) decreased from 89 mm on June 25 to 5 mm on July 23 on control plants, and decreased from 57 mm to 2 mm on N-deficient plants. The concentration of IAA in fruiting branches decreased from 78 to 31 ng/g in controls and from 51 to 32 ng/g in N-deficient fruiting branches. The amount of IAA per fruiting branch (not including squares and bolls) decreased from 66 to 7 ng in controls and decreased from 29 to 3 ng in N-deficient fruiting branches. Decreases in IAA may be a factor in cutout.